Effect of pesticides in honeybee semiochemicals.

ROSSINI C; GONZALES,A; PORRINI M; GARRIDO,M; EGUARAS M

Bogota

Congreso; III Congress of Latin American Association of Chemical Ecology; 2014

ALAEQ

Semiochemicals are important clues that regulate colony homeostasis in Apis mellifera. It is well known that cuticular hydrocarbons (CHC) are involved in social recognition and ethyl oleate (EO) plays a role as primer pheromone in honeybees. Different pathogens can alter these semiochemicals. We here present a study on the effect of 3 widely used chemical acaricide treatments on CHC and EO when applied to Nosema ceranae-infected and uninfected bees. To test de effect of N. ceranae infection and amitraz, coumaphos and fluvalinate on CHC and EO we follow a procedure previously described1. Hexane extracts from healthy and infested bees were partitioned by SPME. Two of the fractions obtained were analyzed by GCMS. Quantification was done using arachidonic acid methyl ester as internal standard for OE and normalizing the total area in the case of CHC. CHC showed no overall differences among the 8 experimental groups tested (ANOVA tests, P ˃ 0.05). The only difference found was between methylalcanes in healthy bees (5.5 ± 0.5) and Nosema-infected bees 8.4 ± 1.4 g (t-test, P ˂ 0.05). On the other hand, in this study EO was not higher in Nosema-infected bees compared to healthy ones (5 ± 1 and 10 ± 4 g respectively), as it was previously reported1. However, when the 3 chemicals were applied separately, EO did increase compared to untreated healthy bees. Further, in the case of coumaphos, EO increased in both, healthy and infected bees (34 ± 9 and 42 ± 13 g respectively). Besides, the levels of two other ethyl esters (linolenic and olenic) were also affected by the treatments. While we did not find an effect of N. ceranae infection on the bee pheromones, the use of chemical treatments to prevent or treat comb diseases and commonly found contaminating honey may alter the normal homeostasis of the colony, irrespective of the colony being ill or not.